That is actually fairly typical. A lot of real estate brokerages will want separate staff members who only work on one side. From knowing a couple- the new goal for a real estate firm is a broker, an assistant, a listing agent, a buyers agent, admin and an all purpose agent. In that order. And then you start multiplying the various positions. You also start seeing realtors who specialize in certain types of property such as single family, certain parts of town, historic, multi family, rentals, etc. as an example Thomas' brother was one of the first people to really focus on the high end downtown market.
At the present moment the Charleston real estate market is hot and sales are actually higher than you would expect of a metro this size. Because the desireable areas are pricey you see first time buyers having to move up because of size, older buyers downsizing to get into a better area, people moving for schools and people moving from older to newer. And the whole thing is impacted by all the transplants who come from out of town.
I do not think Craig's rental is in Mt Pleasant judging by the stores/businesses we saw them drive past. Mt Pleasant basically has 3 main roads so its pretty easy to figure out locations and a couple of combos (maybe a Red Roof next to a Bojangles and a multi story building behind the McDonalds) did not look familiar. Also if he bought in outer West Ashley, the Dorchester Road area or Summerville/Goose Creek he would get in at a lower cost. Mt Pleasant home prices (and the taxes based on the value) typically make purchasing something as a rental less desirable. Even close in West Ashley no longer functions well for rental purchases.
This show has turned into a giant game of 'where did they film that' and realizing when they use a dummy exterior/neighborhood.